Abstract:Considering the low water and fertilizer use efficiencies with flood irrigation in sandy soil of Yulin, Northern Shaanxi, the effects of different water and fertilizer supplies on potato growth, yield and water and fertilizer use efficiencies were investigated through the field drip fertigation experiments. There were three water levels: W1(60%ETc), W2(80%ETc) and W3(100%ETc), and three fertilizer levels: F1(100-40-150kg/hm2), F2(175-60-225kg/hm2) and F3(250-80-300kg/hm2), resulting in a total of nine treatments. Based on those, key indicators (e.g., growth and yield) of potato in response to different irrigation water and N, P and K amounts were further analyzed. Results showed that different water and fertilizer amounts significantly influenced the plant height, leaf area index, dry weight, yield, water use efficiency (WUE), partial factor productivity of fertilizer (PFP), different tuber quality, yield related relations and economic benefits. The growth, yield and PFP were increased with the increase of irrigation amount, and W3 was more beneficial to growth of potato. However, the water use efficiency of W3 was significantly lower than those of W1 and W2. The average water use efficiency of W1 was 5.83% and 13.05% higher than those of W2 and W3. The impact of fertilizer on growth and yield showed an increasing and then decreasing trend, and yield reached the maximum of 59394.98kg/hm2 at W3F2 level. The water use efficiency of F2 was significantly greater than those of F1 and F3. Linear fitting revealed a positive relationship between plant height, leaf area index, dry weight and yield of potato within a certain range. Comprehensive analysis indicated that the appropriate irrigation and N, P and K amounts can not only maintain the good growth of potato, but also can obtain great yield and economic benefits. From the point of view of obtaining high yield and saving water and fertilizer, W3F2 (100%ETc, 175-60-225kg/hm2) can be used as an appropriate combination under the present experimental conditions.
